wrentmore



pril 10, 1928.

E. L. WRENTMORE INTERNAL COMBUSTION ENGINE Fil 2;- 25 1920 4 Sheets-5heet l ,Invcnfm'.

April 10,1928.

E. L. WRENTMORE INTERNAL COMBUSTION ENGINE FiIed Aug-ZS, 1920 4 Sheets-Sheet 2 mm my E. L. WRENTMORE INTERNAL COMBUSTION ENGINE April 10, 1928.

4 Sheefis-Sh'eet 3 Filed 511;;- 25, 1920 April 10, 1928.

E. L. WRENTMORE INTERNAL COMBUSTION ENGINE Filed -25 1920 4 Sheets-Sheet 4 MI W Patented Apr. 10, 1928.

I UNITED STATES PATENT OFFICE.

nnivnsr 1.. wnnnrnonn, or wannnn, OHIO; (ii/ins.) Manna v. "wannrnonn ADMINIS- mineral); or SAID manner L. WRENTMORE, nncnnsnn. Q

rnrnnnn-n-oonnnsrron ENGINE.

Application filed August 25, 1920. Serial 1%.. 405,919.

This invention relates to plural cylinder engines of the ll-type, in which, during each revolution of the crank shaft, there will be half as many equally spaced explosive impulses as there are cylinders.

The objects of the invention are to increase the etliciency of such an engine, and to renderit possible to arbitrarily determine the anglebetween the cylinders of the two rows regardless of the number of cylinders, provided they are multiplesof four.- This makes it possible to make the angle very small between the cylinders, which is desirable because the engine may be thereby made very narrow, and because also the moving parts will be in better balance, and because also the problems of providing-efficient lubrication will be simplified.

The inventionincludes, as an essential part, a novel crankshaft having certain characteristics of construction which are shown in the drawing and are hereinafter described and definitely pointed out in the appended claims, in which said crank shaft, per se, as well as combinations of the crank shaft with other parts of the engine are definitely set forth.

The invention in its broader aspects is ap plicable to crank shafts for V-type engines, regardless of the number of cylinders, provided the number is four or any greater number which is a multiple of two. The crank shaft isespecially valuable in connection with an eight cylinder engine or with a twelve cylinder engine; and the drawing shows both of these constructions. p

In the drawing, Fig. 1 is a vertical transverse sectional view through the front cylinder of an eight cylinder engine, showing the front cylinder 1 and the associated cylinder 1 in the other row. Fig. 2 isa projected bottom view of an S-cylinder engine in which the invention is embodied; Fig. 3 is a front end view of said crank shaft, and Fig. 4: is a diagrammatic view of said crank shaft showing the relative positions of the crank pins thereof; Fig. 5 is a vertical transverse sectional view through the front cylinder of a 12-cylinder engine, showing also the associated cylinder 1. in the other row; Fig. 6 is a projected bottom view ofsaid engine; Fig. 7 is a front end view of the crank shaft; Fig. 8 is a sectional end view in the plane of line 88 on Fig. 6; Fig. 9 is a sectional end viewon line 9-9 on Fig. 6, and

Fig. 'lO is a diagrammatic view showing the relative positions of the various crank pins of said shaft. I

If in any. engine, the cylinders are arranged in a single row, with their axes in one plane, the crank pins will be disposed in certain radial or diametrical normal. planes whose relation to one anotherdepends upon the number of cylinders. For example, in a l-cylinder engine the crank pins are in a single normal diametrical plane and are arranged in pairs at opposite sides of the crank shaft. In an 8-cylinder engine the normal planes in which the crank pins are disposed are diametrical, and are at right angles to each other. In a 6-cylin-der engine the normal planes are radial planes and are spaced120 apart. In a 12-cylinder engine, the normal planes are diametrical and are spaced apart. In a 10-cylinder engine the normal planes are radial and arespaced 72 apart. It is, however, one of the peculiarities of the present invention that the crank pins do not lie in these normal planes, but are angularly displaced with respect to said planes to an. extent determined by the angle between the two rows of cylinders.

In the 8-cylinder engine the cylinders in one row are consecutively numbered 1, 2, 3, 4, from front to rear; and the cylinders of the other row similarly numbered 1, 2 3,

4. In the IQ-cylinder engine the cylinders in one row are numbered 1 to 6 inclusive, consecutively from front to rear, and the corresponding cylinders in the other row are similarly numbered 1 to 6, inclusive.

In a four or six cylinder engine the cylinders are arranged in pairs, one in each row. In an eight or twelve cylinder engine the cylinders are arranged in groups of. four, two in each row; and the arrangement is such that in each group of four the first and fourth cylinders are in one row, and the second and third cylinders are in the other row. It will be also noted that the cylinders of each associated pair, one in each row, as for example, 1 and 1, are offset longitudinally with respect to each other, that is, one is nearer the front of the engine than the other. By reason of this offset disposition of the cylinders the lower ends of each associated pair may be madeto overlap and therefore the angle between the cylinders in I i The normahp lanes referredto in an 8cyl= inder engine, when the cylinders are in a single row, are indicated by lines A and B in thediagrammatic Big. 4, these lines being at rightangles-to each other. The normal dia'metricalplanes in a 12-cylinder engine are indicated in diagrammatic Big. 10 by the lines 0, D and E.

The angle between the: two rows of cylin- 1 ders may, as stated, be arbitrarily determined, and for the purpose of this descriptioniit will be referred to as angle g.

In an 8 -cylinder engine the two crank pins 11, 11, which are respectively, associated with cylinders 1, 1, are-located on opposite sides o'i the 'axis of the crank shaft, one in advanceof and one behind normal diametri cal-plane A, the angular displacement of each of=these two crank pins from Sfitldl'lOl mal plane being equal to one-half of angle 93 Therefore, when the axis of the crank pin 11- isat its upper dead" center, its axis lies in the plane cpnt-aining the axes of the cylinders in the righthand row of cylinders,

- viewed from the front, At the same instant olers'4;*4-. The crank pin 14 is displaced behind said normal] diametricalplane A,

while the crankpin 14-is displaced in ad Vance of said normal diainetr'ic al plane A;

the angular displacement of each crank pin from said plane being one half of angle 9.

Butwhfle both of the crankpins 11 and" 11 he on the same (right) side of said-normal diametri'cal plane A, (when said plane is vertical) bothof thecranki pins 14, 14,- lie on-the opposite (left)- sideof saidplane A.

The unbalanced: parts of the two crank'pins 11, 11 and their crank arms are therefore counterbalanced unbalanced crank pins"1=4,-14, and 'their associated crank arms.

The crank pins 12*and 12 whichare associat'ed with cylinders 2, 2,- are disposed the former in advance of thenormal diametrical plane'B and the latter behind said normal diafmetri cal plane, the angular displacement of -these'two crank pins from said normal diametrical plane being one-half of the angle 9.? The two crank pins13, 13, respect'ively, associated with the cylinders 3, 3; are displaced 1 compared with the normal diametrical plane B, the former in advance ofandthe latterfbehind said normal-diametrical plane, the degree of displacement with respect to said plane being one half-ofangle g. The two crank pins 12 and 12 are both on one side of said plane, while the crank pins 13, 13 are both on the other side of saidplane, and balance the pins 12, 12.

When the/parts are constructed as above described,the crank pins 11, 12, 13, 14, are all. connected by suitable connecting rods with pistons in the cylinders in the righthandrow of cylinders. The crank pins 11, 12, 13, 14, are all connected by connecting rods with pistons in the lefthand row of cylinders. When the crank pin 11 is at its upper dead center with respect to the cylinder 1 with which it is associated, the crank pin 11 is at its lower dead center with respect to the cylinder 1 with which it is associated. At the same time the crank pin 14 is at its lower dead center with respect to the cylinder 4 with which it is associated, and the crank pin 14 is at its upper dead center with respect to the cylinder 4 with which ity is associated. At the same time the crank pins 12, 12, 13, 13, are midway between their dead centers. with respect to the cylinders with which they are associated. The crank pins 12 and 13 moving toward their upper dead centers with respect to the cylinders 2 and 3 with which they are respectively associated, while the crank pins 12 and 13 are moving down toward their lower dead centers with respect to the cylinders 2 and-3 with which they are respectively associated. For each quarter revolution of the crank shaft two crank pins reach their upper dead centers, one on its compression stroke, the piston andthe other cylinder on its exhaust stroke.

Since the charge in each cylinder is ignited at the end of the compression stroke of-its piston and crank pin it is evident-that there will be an explosive impulse for each quarter 'revolutionof the crank shaft. The firing order in the eight cylinder engine is as follows: 1, 3 ,4, 2, 4, 2, l, 3.

As before stated, the oilcenter crank pins 11 and 11 are counterbalanced by the oilcenter crank pins 14 and 14-, and the oilcenter crank pins12 and 12 are counterbalanced by the OE center crank pins 13 and 13, and therefore an eight cylinder crank shaft is in static balance. It is, howeverfout of balance in different parts of its length. In order to prevent any bending of the crank shaft by reason of that fact a crank bearing 30 is formed on the crank shaft-between each pair oi cranks; andadditionally eachcrank check 20 is extended to the opposite side of the normal diametrical plane to that on which its crank pin lies. To the extent which this crank check is soextcnded and weighted, the lack of balance due to the oil' center location of the crank pin is taken care of and the crank shaft is locally counterbalanced.

The 12Tcylinder crank shaft is shown in Figs. 5 to 10, inclusive. The normal diametrical planes are indicated as before stated by the lines C, D, E, shown in diagrammatic Fig. 10, which also shows the locations of the twelve crank pins with respect to these planes and with each other.

The crank pins 11 and 12, associated with cylinders 1 and 2 are in alignment, and so are the crank pins 11, 12*, associated with cylinders 1 2; but the crank pins 11 and 12 are displaced in advance of the normal diametrical plane 0, while the crank pins 11, 12, are equally displaced behind said plane, the displacement being equal to onehalfof the angle 9 between the two rows of cylinders. The aligned crank pin-s 13, 14, are displaced ahead of the normal diae metrical plane E, while the aligned crank pins 13*, 14", are equally displaced behind said plane E. The crank pins 15, 16, are displaced in advance of the normal diametrical plane D, whilethe crank pins 15 16, are equally displaced behind said diainetrical plane. The displacement of all of said crank pins with respect to said normal diametrical planes is one-half of the angle 9. This produces a crank shaft which is in static balance; and the local unbalanced condition of the crank shaft may be restored, as with the crank shaft first described by, extending each crank check 20 sufficiently to the opposite side of a normal diametrical plane on which the associated crank pin lies. The crank pins 11, 12, 13, 1 1, 15 and 16 are respectively connected by connecting rods 10 with the piston-s P in the cylinders 1 to 6 inclusive in one row; and the crank pins 11, 12, 13*, 14:, 15 and 16 are similarly connected with the pistons P in the cylinders 1, 2, 3, 4, 5 6 a For each sixth of a revolution of this crank shaft,'a piston will come to its upper dead center on its compression stroke, and the charge will be ignited. The charges are ignited alternately in opposite rows of cylinders, the firing order being 1, 3, 5, 2*,

Having described my invention, I claim 1. In an internal combustion engine having a plurality of cylinders arranged in two relatively inclined rows,-which cylinders are arranged in groups offour of which the first and fourth cylinder of each group is in one row and the second and third cylinders of said group is in the other row, with a crank shaft having its crank pins disposed in pairs for co-operation with associated pairs of cylinders,of which one of each pair is in one row and the other is adjacent thereto but in the other row, the crank pins of each pair being disposed onein advance of and one behind the normal plane for said crank pins, the offsetting of said crank pins from said planes being equal to one-half of the angle between the planes in which the two rows of cylinders lie, the crank pins which are in advance of said normal dialnetrical planes being connected with the pistons which are in advance of a vcrtical plane which bisects the angle between the two rows of cylinders, and the other crank pins being connected with the pistons of the cylinders of the other row.

2. A crank shaft havingfour crank pairs each comprising two crank pins which lie on opposite sides of the crank shaft, crank cheeks connecting said crank pins with the crank shaft, and a long crank arm connecting said crank pins with each other,the two crank pins of each crank pair being equally offset to the same side of a dia1netrical plane, the crank pins of one crank pair lying on one side and the crank pins of another pair lying on the opposite side of one diametrical plane, the crank pins of a third '1 pair lying on one side and the crank pins of the fourth pair lying on the opposite sides of a dianietrical plane at right angles to the diametrical plane first mentioned.

3. A crank shaft having four crank pairs each comprising two crank pins which lie on opposite sides of the crank shaft, crank cheeks connecting said crank pins with the crank shaft, and a long crank arm connecting said crank pine with each other, the two crank pins of each crank pair being equally offset to the same side of a diametrical plane, the crank pins of one crank pair lying on one side and the crank pins of another pair lying on the opposite side of one diametrical plane, the crank pins of a third pair lying on one side and the crank pins of the fourth pair lying on the opposite sides of a diamet rical plane at right angles to the diametrical plane first mentioned, said crank shaft having five bearings located at the ends of the crank shaft and between the adjacent crank pairs.

41. In an internal combustion engine, the combination of two rows of cylinders which are inclined in opposite directions and are associated in pairs one cylinder from each row, with a crank shaft having four crank pairs arranged in approximately quartering positions, but with the crank pins of each crank pair offset equally to the same side of a diametrical plane to a degree equal to one half the angle between the two rows of cylinders.

5. In an internal combustion engine, the combination of two rows of cylinders which are inclined in opposite directions and are associated in pairs one cylinder from each row, with a crank shaft having four crank pairs arranged in approximately quarterin positions, but with the crank pins of eac crank pair offset equally to the same side of the diametrical plane to a degree equal to one half the angle between the two rows of cylinders, the crank pins of one pair being on one side of a, certain diametr-ical plane and those of the secondpair on the opposite side of said diametrical plane, andthe crank pins of the other two crank pairs being on opposite sides of a diametrical planeat right angles to the diainetrical plane first mentioned.

6. The combinationof an 8-cylinder engine of the V-type whereof each cylinder is offset lengthwise of the engine and is overlapped transversely with respect to the associated cylinder: in the other row, with a crank shaft having four crank pairs arranged in substantially qu'artering positions, eachjcralnk pair comprising two crank pins which lie on opposite sides of the crankshaft bntfwhich areequally offset to the same side of .a-ndiametrical plane, the two crank pins ofone pair being oifset to one side of a certain diametri'cal plane and the two crank pins of another pair being offset to the opposite side of the same dian'ietrical plane, the crank pins of the third pair being offset to one side of a diametrical plane at right angles to the diarnet-rical plane first nientioned, andthe crank pins of the fourth pair being offset to the oppositeside of the last mentioned diametrical plane, pistons in said cylinders, and connecting rods connecting the pistons with the crank pins.

'7. In an S-cylinder engine of the V-type,

neeaeei the combination of two rows of oppositely inclined cylinders whereof each cylinder of one row is associated with a cylinder of the other row and is offset lengthwise of the engine and overlapped transversely with respect thereto, the first and third cylinders in one row being in advance of the correspond ing ('iylinders of the other row, and the second and fourth cylinders in the first row being in the rear of corresponding cylinders in the other row, with a S-bcaring crank shaft havingfour crank pairs arranged in approximately quartering positions, each crank pair including two crank pins which lie on opposite sides of the crank shaft but are equally offset to the same side of a diainetrical plane, the two end crank pairs, when the crank shaft is in a certain position being respectively offset the one to the right and the other to the left of a vertical dianietrical plane, and the two crank pins of each of the two intermediate crank pairs being respectively offset above and below a horizontal dianietrical plane, pistons in the cylinders, and connecting rods connecting said pistons with the several associated crank pins.

In testimony whereof, I hereunto afiix my signature.

ERNEST L. WRENTMORE. 

